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皱缩型收缩是低中等密度桉树人工林木材被用于实木产品加工时最难以克服的缺陷之一。为此,本研究对种植在广西国营东门林场的3 种易皱缩桉树(尾叶桉,巨桉,尾巨桉)木材的基本密度,微纤丝角(MFA),纤维双倍壁厚(DWT), 射线薄壁组织率(RP), 单位胞壁收缩率,总收缩率和残余皱缩几个与皱缩相关的材性指标进行了研究。结果表明:1)单位胞壁收缩率与基本密度具有极强的线性正相关性,与纤维双倍壁厚表现出中等至强的线性正相关性,而与射线薄壁组织率和微纤丝角呈现弱至中等的线性负相关性。基本密度能作为单独因子很好的预测单位胞壁收缩率(R2≥0.9412); 2)总收缩率与基本密度、纤维双倍壁厚、射线薄壁组织率具有弱至中等的线性正相关性,与微纤丝角呈现线性弱的负相关性。基本密度和上述3 个解剖指标均不能单独作为预测总收缩率的因子(R2≤0.5712); 3)残余皱缩与基本密度和纤维双倍壁厚表现弱的线性负相关性,与微纤丝角呈现弱的线性正相关性,与射线薄壁组织率则表现了强的线性正相关性。因此,射线薄壁组织率是较好的残余皱缩的预测因子(R2≥0.7454)。图6 表3 参39。
Shrinkage shrinkage is one of the most insurmountable drawbacks of low and medium density Eucalyptus plantation timber used in the processing of solid wood products. In this study, we studied the basic density, microfibril angle (MFA), doubling fiber thickness of three kinds of easily-shrinkable eucalyptus (Eucalyptus urophylla, E. grandis and E. urophylla) (DWT), ray parenchyma (RP), unit cell wall shrinkage, total shrinkage and residual shrinkage were compared with several shrinkage-related material properties were studied. The results showed that: 1) there was a strong linear positive correlation between the cell wall shrinkage and the basic density, showing a moderate to strong positive linear correlation with the double fiber wall thickness, The corners show a weak to moderate linear negative correlation. Basal density can be a good predictor of cell wall shrinkage (R2≥0.9412) as a single factor; 2) There is a weak to moderate linear positive correlation between total shrinkage and basic density, fiber double wall thickness, and ray parenchyma rate , And the microfibril angle showed a linear weak negative correlation. The basic density and the above three anatomical indexes can not be used alone as a factor to predict the total shrinkage rate (R2≤0.5712); 3) The linear negative correlation between residual shrinkage and basic density and double fiber wall thickness is weak, Corners show a weak linear positive correlation with a strong linear positive correlation with the rate of radiation parenchyma. Therefore, the ray ply rate is a good predictor of residual shrinkage (R2> 0.7454). Figure 6 Table 3 Reference 39.